Nerve Root Avulsion Injury Research Articles

ОЦЕНКА ИЗМЕНЕНИЙ КОРЕШКОВ ШЕЙНОГО И ПЛЕЧЕВОГО СПЛЕТЕНИЙ ПРИ АВУЛЬСИОННЫХ ПОВРЕЖДЕНИЯХ

Introduction. Methods of radiologic imaging have taken a leading place in the assessment of damage to the roots of the cervical and brachial plexuses. One of the variants of damage is avulsion injury with partial or complete detachment of the nerve root at the place of its exit from the spinal cord. The leading position in the visualization of such lesion, until recently, was occupied by computed tomographic myelography. At the same time, it has a number of disadvantages, and therefore the search for alternative imaging methods remains relevant. Aim. To study the opportunities of assessing avulsion damage to the roots of the cervical and brachial ple¬xuses in avulsion injuries in patients with traction injury using 3D-CISS technique in comparison with CT-myelography. Materials and methods. The study included 50 patients of both sexes hospitalized at the Federal State Budgetary Institution "Federal Neurosurgical Center " of the Ministry of Health of Russia with avulsion injuries in the roots of the cervical or brachial plexuses of traction origin. The studies were performed on MRI scanners with a magnetic field strength of 1.5 Tesla using the 3D-CISS MRI technique and CT-myelography in a neurosurgical hospital using a Siemens SOMATOM Definintion AS spiral tomograph. The patients underwent surgical reconstruction of the avulsion lesion of the nerve roots. Results. Features of injuries to the nerve roots of the cervical and brachial plexus: possible visualization of pseudomeningocele with CT-myelography and 3DCISS technique, visualization of an interrupted root course with 3D-CISS technique. With the 3DCISS technique, the data corresponded to intraoperative data more often than with CT-myelography. The results of the MRI method using the 3D-CISS technique are more reliable in comparison with CT myelography in the assessment of pathological changes in the nerve roots. Conclusion. 3D-CISS is a more effective technique for visualizing nerve root avulsion injury compared to CT-myelography.

PLGA-PEG-PLGA hydrogel with NEP1-40 promotes the functional recovery of brachial plexus root avulsion in adult rats.

Adult brachial plexus root avulsion can cause serious damage to nerve tissue and impair axonal regeneration, making the recovery of nerve function difficult. Nogo-A extracellular peptide residues 1-40 (NEP1-40) promote axonal regeneration by inhibiting the Nogo-66 receptor (NgR1), and poly (D, L-lactide-co-glycolide)-poly (ethylene glycol)-poly (D, L-lactide-co-glycolide) (PLGA-PEG-PLGA) hydrogel can be used to fill in tissue defects and concurrently function to sustain the release of NEP1-40. In this study, we established an adult rat model of brachial plexus nerve root avulsion injury and conducted nerve root replantation. PLGA-PEG-PLGA hydrogel combined with NEP1-40 was used to promote nerve regeneration and functional recovery in this rat model. Our results demonstrated that functional recovery was enhanced, and the survival rate of spinal anterior horn motoneurons was higher in rats that received a combination of PLGA-PEG-PLGA hydrogel and NEP1-40 than in those receiving other treatments. The combined therapy also significantly increased the number of fluorescent retrogradely labeled neurons, muscle fiber diameter, and motor endplate area of the biceps brachii. In conclusion, this study demonstrates that the effects of PLGA-PEG-PLGA hydrogel combined with NEP1-40 are superior to those of other therapies used to treat brachial plexus nerve root avulsion injury. Therefore, future studies should investigate the potential of PLGA-PEG-PLGA hydrogel as a primary treatment for brachial plexus root avulsion.

Surface Electromyographic Biofeedback as a Rehabilitation Tool for Patients with Global Brachial Plexus Injury Receiving Bionic Reconstruction.

In patients with global brachial plexus injury and lack of biological treatment alternatives, bionic reconstruction, including the elective amputation of the functionless hand and its replacement with a prosthesis, has recently been described. Optimal prosthetic function depends on a structured rehabilitation protocol, as residual muscle activity in a patient's arm is later translated into prosthetic function. Surface electromyographic (sEMG) biofeedback has been used during rehabilitation after stroke, but has so far not been used in patients with complex peripheral nerve injuries. Here, we present our rehabilitation protocol implemented in patients with global brachial plexus injuries suitable for bionic reconstruction, starting from identification of sEMG signals to final prosthetic training. This structured rehabilitation program facilitates motor relearning, which may be a cognitively debilitating process after complex nerve root avulsion injuries, aberrant re-innervation and extra-anatomical reconstruction (as is the case with nerve transfer surgery). The rehabilitation protocol using sEMG biofeedback aids in the establishment of new motor patterns as patients are being made aware of the advancing re-innervation process of target muscles. Additionally, faint signals may also be trained and improved using sEMG biofeedback, rendering a clinically "useless"muscle (exhibiting muscle strength M1 on the British Medical Research Council [BMRC] scale) eligible for dexterous prosthetic hand control. Furthermore, functional outcome scores after successful bionic reconstruction are presented in this article.

Pretreatment of nerve grafts with resveratrol improves axonal regeneration following replantation surgery for nerve root avulsion injury in rats.

Replantation of the avulsed nerve root has been proposed for the treatment of severe brachial plexus injury for several decades. However, due to the complexity of the technique and limited functional improvement, practical applications are yet to be implemented. In the present study, we investigated the effect of pretreatment with resveratrol on nerve autografts used for replantation surgery in a rat model of nerve root avulsion. Resveratrol pretreatment was performed using an explant culture technique. Two surgical procedures were performed. During the first surgery, Sprague-Dawley rats were subjected to left C6 nerve root avulsion, and nerves were harvested for autografting. The harvested grafts were explant-cultured for 1 week. A second procedure was performed to replant the C6 nerve root using the explant-cultured nerve graft 1 week after the first procedure. Histological and immunohistochemical analyses were performed 8 weeks after the second procedure. We first compared findings between explant-cultured nerve grafts and fresh nerve grafts, following which we compared findings between explant-cultured grafts pretreated with and without resveratrol. Changes induced within nerve grafts by 1 week of explant culture with or without resveratrol were investigated in vitro. There was no significant difference in outcomes between 1 week-explant-cultured and fresh nerve grafts. Addition of resveratrol to the explant culture medium resulted in a significant increase in the number and myelin thickness of regenerated axons, and in the number of regenerating motor neurons in the C6 spinal cord segment. In vitro analyses revealed that nerve grafts pretreated with resveratrol exhibited significant increases in glial cell line-derived neurotrophic factor (GDNF) expression and the number of dedifferentiated Schwann cells. Resveratrol may promote axonal regeneration following replantation surgery for the treatment of nerve root avulsion injury; however, further studies are required to verify these findings in humans.

SIRT1 activation with neuroheal is neuroprotective but SIRT2 inhibition with AK7 is detrimental for disconnected motoneurons

Sirtuin 1 (SIRT1) activity is neuroprotective, and we have recently demonstrated its role in the retrograde degenerative process in motoneurons (MNs) in the spinal cord of rats after peripheral nerve root avulsion (RA) injury. SIRT2 has been suggested to exert effects opposite those of SIRT1; however, its roles in neurodegeneration and neuron response after nerve injury remain unclear. Here we compared the neuroprotective potentials of SIRT1 activation and SIRT2 inhibition in a mouse model of hypoglossal nerve axotomy. This injury induced a reduction of around half MN population within the hypoglossal nucleus by a non-apoptotic neurodegenerative process triggered by endoplasmic reticulum (ER) stress that resulted in activation of the unfolded protein response mediated by IRE1α and XBP1 by 21 days post injury. Both SIRT1 activation with NeuroHeal and SIRT2 inhibition with AK7 protected NSC-34 motor neuron-like cells against ER stress in vitro. In agreement with the in vitro results, NeuroHeal treatment or SIRT1 overexpression was neuroprotective of axotomized hypoglossal MNs in a transgenic mouse model. In contrast, AK7 treatment or SIRT2 genetic depletion in mice inhibited damaged MN survival. To resolve the in vitro/in vivo discrepancies, we used an organotypic spinal cord culture system that preserves glial cells. In this system, AK7 treatment of ER-stressed organotypic cultures was detrimental for MNs and increased microglial nuclear factor-κB and the consequent transcription of cytotoxic pro-inflammatory factors similarly. The results highlight the importance of glial cells in determining the neuroprotective impact of any treatment.

Results of Distal Nerve Transfers in Restoration of Shoulder Function in C5 and C6 Root Avulsion Injury to the Brachial Plexus

Background The lack of shoulder function following brachial plexus injury is a debilitating condition. Nerve root avulsion injury precludes a direct nerve repair. Under these circumstances, distal nerve transfer is a well-established technique in the restoration of shoulder abduction and external rotation. Methods Thirty patients with C5 and C6 root avulsion injury were treated with distal nerve transfers in the period between February 2009 and December 2012.The average denervation period was 5.6 months. Shoulder function was restored by posterior transfer of distal part of the spinal accessory nerve into the suprascapular nerve and transfer of the long head triceps branch of radial nerve to the anterior branch of axillary nerve. An additional nerve transfer was performed in four patients with winged scapula by transferring a part of thoracodorsal nerve into the long thoracic nerve. Results Twenty-seven patients recovered shoulder abduction; 18 scored M4 and 9 scored M3. Range of abduction averaged 118 degrees (range, 90–170 degrees). Nineteen patients restored external rotation with an average of 53 degrees (range: 30–70 degrees). Three patients failed to recover shoulder abduction though the joint regained stability. External rotation remained severely restricted in 11 patients. At final follow-up, winging of scapula improved in three of four patients following reinnervation of the serratus anterior muscle. Conclusion Nerve transfers, when performed close to the target muscles, restore good range and strength of shoulder abduction in most patients with C5 and C6 root avulsion injuries. However, return in external rotation is not as good as the recovery in abduction.

Surgical reconstruction of spinal cord circuit provides functional return in humans.

This mini review describes the current surgical strategy for restoring function after traumatic spinal nerve root avulsion in brachial or lumbosacral plexus injury in man. As this lesion is a spinal cord or central nervous injury functional return depends on spinal cord nerve cell growth within the central nervous system. Basic science, clinical research and human application has demonstrated good and useful motor function after ventral root avulsion followed by spinal cord reimplantation. Recently, sensory return could be demonstrated following spinal cord surgery bypassing the injured primary sensory neuron. Experimental data showed that most of the recovery depended on new growth reinnervating peripheral receptors. Restored sensory function and the return of spinal reflex was demonstrated by electrophysiology and functional magnetic resonance imaging of human cortex. This spinal cord surgery is a unique treatment of central nervous system injury resulting in useful functional return. Further improvements will not depend on surgical improvements. Adjuvant therapy aiming at ameliorating the activity in retinoic acid elements in dorsal root ganglion neurons could be a new therapeutic avenue in restoring spinal cord circuits after nerve root avulsion injury.

New Treatments for Spinal Nerve Root Avulsion Injury.

Further progress in the treatment of the longitudinal spinal cord injury has been made. In an inverted translational study, it has been demonstrated that return of sensory function can be achieved by bypassing the avulsed dorsal root ganglion neurons. Dendritic growth from spinal cord sensory neurons could replace dorsal root ganglion axons and re-establish a reflex arch. Another research avenue has led to the development of adjuvant therapy for regeneration following dorsal root to spinal cord implantation in root avulsion injury. A small, lipophilic molecule that can be given orally acts on the retinoic acid receptor system as an agonist. Upregulation of dorsal root ganglion regenerative ability and organization of glia reaction to injury were demonstrated in treated animals. The dual effect of this substance may open new avenues for the treatment of root avulsion and spinal cord injuries.

Diagnosis of nerve root avulsion injuries in adults with traumatic brachial plexopathies: MRI compared with CT myelography

Background: Computed tomography myelography (CTM) has been broadly adopted as the ‘gold standard’ imaging technique in the diagnosis of nerve root avulsion injuries in traumatic brachial plexopathies. CTM has the distinct advantage of better spatial resolution than magnetic resonance imaging (MRI); however, this technique is invasive and can result in significant patient discomfort. MRI, therefore, seems relatively more advantageous as it is less invasive (requires no lumbar puncture), lacks radiation exposure, has no adverse reactions related to intrathecal contrast agents and confers excellent soft-tissue contrast. Objectives: To compare the sensitivity and specificity of MRI with CTM in the diagnosis of preganglionic nerve root avulsion injuries in adults with traumatic brachial plexopathies at the Inkosi Albert Luthuli Central Hospital.Method: A retrospective comparative analysis was performed on 16 adult patients with traumatic preganglionic brachial plexopathies who underwent both MRI and CTM at Inkosi Albert Luthuli Central Hospital. Radiologists experienced in both CTM and MRI interpreted the data and a comparison was made using CTM as the gold standard. Results: The sensitivity and specificity for MRI detecting preganglionic nerve root avulsion injuries and pseudomeningoceles was 82% and 100% respectively. The interobserver agreement between CTM and MRI for the detection of preganglionic nerve root avulsion injuries was 81.25% (Kappa = 0.77) and 87.5% (Kappa = 0.84) for the detection of pseudomeningoceles. Conclusion: MRI was as sensitive as CTM at detecting preganglionic nerve root avulsion injuries and pseudomeningoceles of spinal nerve roots C7–T1 of the brachial plexus. Some mild discrepancies existed at the C5 and C6 nerve root levels. Owing to the invasiveness of the procedure and resultant patient discomfort, CTM should be reserved for complicated cases or for patients with contraindications to MRI.

The neuroprotective effect of erythropoietin on spinal motor neurons after nerve root avulsion injury in rats.

The rapid death of many spinal motor neurons after nerve root avulsion injury results in limited functional recovery following replantation surgery of avulsed nerves into the spinal cord. Therefore, we investigated the neuroprotective effect of erythropoietin (EPO) on motor neurons after nerve root avulsion injury using a rat model. After C6 nerve root avulsion injury, EPO (2680 U/kg) was injected subcutaneously once a day for 3 consecutive days with various starting time points. At 28 and 56 days after injury, histological and immunohistological investigations were performed. EPO-treated rats showed a significant increase in the number of surviving motor neurons at day 28 when the initial dose was started within 96 h after injury. In EPO-treated rats, superoxide formation in the motor neurons and proliferation of microglia were markedly suppressed in the acute phase. GAP-43-positive surviving motor neurons were significantly increased in EPO-treated rats at day 28. However, at 56 days after surgery, EPO-treated rats showed a much greater decrease of surviving motor neurons compared with those at day 28. The neuroprotective effect of EPO is not long lasting, but may prolong the time before replantation surgery.

Complications of contralateral C-7 transfer through the modified prespinal route for repairing brachial plexus root avulsion injury: a retrospective study of 425 patients.

In this report, the authors review complications related to the modified prespinal route in contralateral C-7 transfer for repairing brachial plexus nerve root avulsion injury and suggest a prevention strategy. A retrospective, nonselected amalgamation of every case of modified contralateral C-7 transfer through the prespinal route was undertaken. The study population comprised 425 patients treated between February 2002 and August 2009. The patients were managed according to a standardized protocol by one senior professor. The surgical complications were grouped into one of the following categories: those associated with tunnel making through the prespinal route, those related to the dissection and transection of the contralateral C-7 nerve root, and those that occurred in the postoperative period. The study population included 379 male and 46 female patients whose average age was 21 years (range 3 months to 56 years). A total of 401 patients were diagnosed with traumatic brachial plexus injury, the leading cause of which was motor vehicle accident, and 24 patients were diagnosed with obstetrical brachial plexus palsy. The contralateral C-7 nerve root was cut at the proximal side of the division portion of the middle trunk in 15 cases and sectioned at the distal end of the anterior and posterior divisions in 410 cases. The overall incidence of complications was 5.4% (23 of 425). Complications associated with making a prespinal tunnel occurred in 12 cases, including severe bleeding due to vertebral artery injury during the procedure in 2 cases (0.47%), temporary recurrent laryngeal nerve palsy in 5 cases (1.18%), pain and numbness in the donor upper extremity during swallowing in 4 cases (0.94%), and dyspnea caused by thrombosis of the brainstem 42 hours postoperatively in 1 case (0.24%); this last patient died 38 days after the operation. Complications related to exploration and transection of the contralateral C-7 nerve root occurred in 11 cases, including deficiency in extensor strength of the fingers and thumb in 4 cases (0.94%) due to injury to the posterior division of the lower trunk, unbearable pain on the donor upper extremity in 3 cases (0.71%), Horner's syndrome in 2 children (0.47%) who suffered birth palsy, a section of C-6 nerve root mistaken as C-7 in l case (0.24%), and atrophy of the sternocostal part of the pectoralis major in 1 case (0.24%). The most serious complications of using the modified prespinal route in contralateral C-7 transfer were vertebral artery laceration and injury to the posterior division of the lower trunk. The prevention of such complications is necessary to popularize this surgical procedure and attain good long-term clinical results.

A new cervical nerve root avulsion model using a posterior extra-vertebral approach in rats

BackgroundThe nerve root avulsion injury causes decrease of motor neurons in the spinal ventral horn. To investigate the motoneuron death after avulsion injury in rats, the intradural root avulsion procedure is usually used, although it is technically demanding and associated with a risk of unexpected spinal cord damage. We have developed a new cervical nerve root avulsion procedure in rats and investigated the validity of our procedure.MethodsOur procedure is using a posterior approach and pulling the C6 nerve root outside the vertebral foramen without intradural procedures. The lateral third of the lateral mass is needed to be resected before pulling the nerve root. The accomplishment of our procedure is judged by confirmation of the bifurcated stump of the avulsed nerve root and the leakage of the spinal fluid from vertebral foramen. At first, four Sprague–Dawley (SD) rats were used for the examination of C6 motor neuron distribution in the normal spinal cord. Then, 40 SD rats were divided into following four groups and the survival rate of motor neuron was examined. (A) an intradural avulsion group, (B) an intradural rhizotomy group, (C) our extravertebral avulsion group, and (D) an extravertebral rupture group. Another 26 SD rats were used for the examination of histomorphorogic changes in the spinal cord after our extra-vertebral avulsion procedure.ResultsAt 28 days after injury, the percentage of surviving motor neurons in groups A (39.0 ± 2.1%) and C (47.5 ± 7.1%) were significantly lower than those in groups B (77.1 ± 12.3%) and D (98.9 ± 9.9%). Compared with other groups, our procedure was easier and associated with less unexpected spinal cord damage. Although the length of the distal stump of the extravertebrally avulsed ventral rootlets was varied between 1.5 and 3.2 mm, this difference did not affect motoneuron death. The extravertebral avulsion injury showed intraspinal bleeding along the motoneuron axons, glial reaction and macrophage infiltration in the lesioned side of the ventral horn.ConclusionsOur extravertebral avulsion procedure is simple and reproducible. It would become a useful tool for the study of cervical nerve root avulsion injury.

Anatomical feasibility of transferring the obturator and genitofemoral nerves to repair lumbosacral plexus nerve root avulsion injuries

Nerve transfer is a valid surgical procedure for restoring lower-extremity function after lumbosacral plexus nerve root avulsion. We determined the anatomical feasibility of transferring the obturator and genitofemoral nerves for this purpose. The obturator, genitofemoral and femoral nerves, and the S1 and S2 nerve roots on both sides were exposed in 10 cadaver specimens. We traced all nerves to their origins. The lengths of the obturator and genitofemoral nerves were measured from their origins to their exits from the abdominal cavity. The transverse and longitudinal diameters of all nerves were measured. Specimens were obtained to determine the total number of myelinated fibers in each nerve. The proximal part of the left obturator nerve was anastomosed with the distal part of the right femoral nerve, between the vertebrae and the peritoneum, with an overlap of 2-3 cm. Similarly, the proximal parts of the right obturator and genitofemoral nerves were anastomosed with the ipsilateral S1 and S2 nerve roots, respectively, with an overlap of 2-4 cm. The obturator nerve contained approximately one-third of the number of fibers (4,300-7,800) presenting in the femoral nerve (13,500-21,000). Similarly, the number of fibers found in the S1 nerve root was in the range 5,200-8,900. The genitofemoral nerve contained approximately half the number of fibers (3,000-4,500) presenting in the S2 nerve root (4,600-8,400). The obturator and genitofemoral nerves could be suitable donor nerves for repairing lumbosacral plexus nerve root avulsion.

Utility of electrodiagnostic testing and computed tomography myelography in the preoperative evaluation of neonatal brachial plexus palsy

The rate of neonatal brachial plexus palsy (NBPP) remains 0.4%-4% despite improvements in perinatal care. Among affected children, the extent of brachial plexus palsy differs greatly, as does the prognosis. Controversial elements in management include indications and timing of nerve repair as well as type of reconstruction in patients in whom function will ultimately not be recovered without surgical intervention. Differentiating preganglionic (avulsion) from postganglionic (rupture) lesions is critical because preganglionic lesions cannot spontaneously recover motor function. Distinguishing between these lesions at initial presentation based on clinical examination alone can be difficult in infants. The purpose of the present study was to determine the sensitivity of preoperative electrodiagnostic studies (EDSs) and CT myelography (CTM) in determining the presence of nerve root rupture and avulsions in infants with NBPP. After receiving institutional review board approval, the authors conducted a retrospective review of patients referred to the Neonatal Brachial Plexus Program between 2007 and 2010. Inclusion criteria included children who underwent brachial plexus exploration following preoperative EDSs and CTM. The CTM scans were interpreted by a staff neuroradiologist, EDSs were conducted by a single physiatrist, and intraoperative findings were recorded by the operating neurosurgeon. The findings from the preoperative EDSs and CTM were then compared with intraoperative findings. The sensitivities and 95% confidence intervals were determined to evaluate performance accuracy of each preoperative measure. Twenty-one patients (8 male amd 13 female) met inclusion criteria for this study. The sensitivity of EDSs and CTM for detecting a postganglionic rupture was 92.8% (CI 0.841-0.969) and 58.3% (CI 0.420-0.729), respectively. The sensitivity for EDSs and CTM for preganglionic nerve root avulsion was 27.8% (CI 0.125-0.509) and 72.2% (CI 0.491-0.875), respectively. In cases in which both CTM and EDSs gave concordant results, the sensitivity for both modalities combined was 50.0% (CI 0.237-0.763) for avulsion and 80.8% (CI 0.621-0.915) for rupture. Overall, EDSs were most useful in identifying ruptures, particularly in the upper plexus, whereas CTM was most sensitive in identifying avulsions in the lower plexus. Knowledge of the spinal nerve integrity is critical for early management of patients with NBPP. Surgical management, in the form of nerve repair/reconstruction, and optimal prognostication of NBPP depend on the accurate diagnosis of the level and type of lesion. Both EDSs and CTM scans must always be interpreted in the context of a comprehensive evaluation of the patient. They provide supplemental information (in addition to the physical examination) for early detection of nerve root rupture and avulsion injuries, aiding surgical decision making and preoperative planning for NBPP. Continued advances in imaging, EDSs, and microsurgical nerve repair techniques will allow surgeons to achieve greater success for functional recovery in management of NBPP.

Contralateral C7 nerve root transfer to neurotize the upper trunk via a modified prespinal route in repair of brachial plexus avulsion injury

In this report, we present our experience on the repair of brachial plexus root avulsion injuries with the use of contralateral C7 nerve root transfers with nerve grafting through a modified prespinal route. The outcomes of the contralateral C7 nerve root transfer to neurotize the upper trunk and C5/C6 nerve roots of the total or near total brachial plexus nerve root avulsion injury in a series of 41 patients were evaluated. The contralateral C7 nerve root that was dissected to the distal end of the divisions, along with the sural nerve graft, were placed underneath the anterior scalene and longus colli muscles, and then passed through the retro-esophageal space to neurotize the recipient nerve. The mean length of the dissected contralateral C7 nerve root was 6.5 ± 0.7 cm, and the mean length of sural nerve graft was 6.8 ± 1.9 cm. The suprascapular nerve was neurotized additionally by the phrenic nerve or the terminal motor branch of accessory nerve in some patients. The mean length of the follow-up was 47.2 ± 14.5 months. The muscle strength was graded M4 or M3 for the biceps muscle in 85.4% of patients, for the deltoid muscle in 82.9% of patients, and for the upper parts of pectoral major in 92.7% of patients. The functional recovery of shoulder abduction in the patients with the additional suprascapular nerve neurotization was remarkably improved. The modified prespinal route could significantly reduced the length of nerve graft in the contralateral C7 nerve root transfer to the injured upper trunk in brachial plexus root avulsion injury, and it may improve the functional outcomes, which deserves further investigations.

Imaging and electrodiagnostic work-up of acute adult brachial plexus injuries

Imaging and electrodiagnostic studies form an essential part of the evaluation of the patient with traumatic brachial plexopathy, enabling clarification of surgical options, prognostication of outcome and formulation of postoperative management. The primary objective of imaging is to identify pre-ganglionic injury indicative of nerve root avulsion. The presence of one or more nerve root avulsion injuries is a critical factor in surgical decision-making and the prognosis of surgical reconstruction. CT myelography is the current imaging modality of choice for this purpose. Initial electrodiagnostic (EDX) testing is ideally performed no sooner than 4 weeks following injury unless otherwise clinically indicated. Follow-up testing can be helpful at approximately 6 week intervals. The sensory nerve amplitudes are the most important component of nerve conduction testing in distinguishing between pre- and post-ganglionic injuries. Electromyographic studies will also assist in the determination of a pre- from post-ganglionic injury, the level of plexus involvement and identify potential donor nerves that may be suitable for use as transfers.

A comparative histological analysis of two models of nerve root avulsion injury in the adult rat

This study has investigated the reliability of the artificial surgical model dorsal root rhizotomy (DRR), to the surgical tearing of the roots, avulsion, that occurs clinically. Root avulsion of the limb nerves is common in high-impact motor vehicle accidents and results in paraesthesia, paralysis and intractable pain. Limited treatment options are largely due to a lack of basic research on underlying mechanisms, and few animal models. We assess this limitation by histologically assessing the spatial and temporal injury profile of dorsal root avulsion (DRA) and DRR within the spinal cord. Rats underwent DRR, DRA or sham surgery to the L3-L6 dorsal roots unilaterally. At 1, 2, 14, and 28 days post injury, immunohistochemical density staining was used to characterize the progression of spinal cord trauma. Neuronal (NeuN) and vascular degeneration (RECA-1), inflammatory infiltrate (ED1, anti-neutrophil), gliosis (Iba1, GFAP) and apoptosis (TUNEL) were assessed. Unilateral DRA produced a prolonged and bilateral glial and inflammatory response, and vascular degeneration compared to transient and unilateral effects after DRR. Transsynaptic neurodegeneration after DRA was greater than after DRR, and progressed across 28 days coinciding with gliosis and macrophage infiltration. Rhizotomy leads to a milder representation of the spinal cord trauma that occurs after 'true' avulsion injury. We recommend DRA be used in the future to more reliably model clinical avulsion injury. Avulsion is an injury with a chronic profile of degenerative and inflammatory progression, and this theoretically provides a window of clinical therapeutic opportunity in treatment of secondary trauma progression.

Prevention and management of the complication of contralateral C7 nerve root transfer through the prespinal route to repair the brachial plexus nerve root avulsion injury

Objective To investigate the occurrence, prevention and management of surgical complication of contralateral C7 nerve root transfer through the prespinal route to repair the brachial plexus nerve root avulsion injury. Methods From Feb. 2002 to Aug. 2009, 425 patients were performed the contralateral C7 nerve root transfer through the prespinal route with this procedure. There were 379 males and 46 females,with the average age of 21 years (range, 3 months to 56 years). The contralateral C7 nerve root was sectioned at the distal of the middle trunk in 15 cases, at the distal of the anterior and posterior division in 410 patients. The surgical complications related to the health C7 nerve root section and the make of tunnel through the prespinal route and others were analyzed retrospectively. Results The incidence rate of complication was 5.2%(22/425). The surgical complications related to the make of prespinal route including 2 cases had the severe bleeding during the operation because of vertebral artery injury; transitory laryrecurrent nerve palsy occurred in 5 cases, the pain and numbness occurred on the donor upper limber in 4 cases when the patients swallowed. The complications related to the section of contralateral C7 nerve root including the extension of finger and thumb was dysfunction in 5 patients after the operation, 3 cases had the severely pain on the health upper limber, Horner's sign occurred on donor side in 2 children suffered birth palsy, and C6 nerve root was mistaken sectioned as C7 in 1 case. Other serious perioperative complication including the thromboses of the cerebral trunk occurred in 1 case 42 hours postoperative and died in hospital 38 days after the operation. Conclusion The procedure of contralateral C7 nerve root transfer through the prespinal route is safe. The effective method to prevent this complication occurrence is to expose the origin segment of vertebral artery when making prespinal route. Key words: Brachial plexus; Nerve transfer; Postoperative complications

Obturator nerve transfer to repair lumbosacral plexus nerve root avulsion injuries: anatomic study and clinical application.

Objective To provide an effective and safe motor donor nerve for the treatment of lumbosacral plexus nerve root avulsion injuries. Methods The obturator nerve, lumbar plexus and sacral plexus on both sides were exposed on 15 cadaver specimens. The length of obturator nerve was measured from its origin to entrance of the foramen obturatum. The transverse diameter and thickness of the obturator nerve and femoral nerve on both sides were measured individually. The obturator nerve and femoral nerve of each specimen was cut into histological slice, and the amount of myelinated nerve fiber was counted respectively. There were five patients including 4 patients with traumatic lumbosacral plexus nerve root avulsion injuries and 1 patient with lumbar plexus nerve root injuries. The contralateral obturator nerve as motor donor nerve transferred through the retroperitoneal route and direct coaptation with the femoral nerve was performed in 4 cases, and ipsilateral obturator nerve was transferred to the S1 nerve root in 1 case. Results The length, transverse diameter and thickness of the obturator nerve was (10.5±0.9) cm, (2.03±0.37) mm and (2.78±0.29) mm individually. The transverse diameter and thickness of femoral nerve were (3.79±0.58) mm, (6.53±0.61) mm individually. The obturator nerve contained 5974±1996 myelinated nerve fibers and the femoral nerve contained 15 860±4350 myelinated nerve fibers. In 3-7 d after the operation, the muscle strength of adduction on the donor lower limber was decreased to grade 2-3. The functional recovery of muscle strength of quadriceps reconstructed by contralateral obturator nerve transfer recovered to grade 4 in 2 cases, grade 2 in 1 case and grade 1 in 1 case between 8 months to 5 years postoperatively. The muscle strength of triceps surae and finger flexor reconstructed by ipsilateral obturator nerve transferring to S1 nerve root recovered to grade 3 after 11 months postoperatively. Conclusion The contralateral or ipsilateral obturator nerve can be used as a new and effective donor nerve for transferring to repair the lumbosacral plexus nerve root avulsion injuries, and there is no obvious deficit on the function of donor lower limber adduction. Key words: Lumbosacral plexus; Wounds and injuries; Nerve transfer; Obturator nerve

Early evacuation of haematoma causing sciatic nerve compression: Yes or no? A comparative case report

A 68-year-old gentleman, Mr. GS, with a past medical history of Atrial Fibrillation (AF) and chronic renal disease (due to chronic glomerulonephritis) presented to a fracture clinic with a history of progressing foot drop and complete anaesthesia of the L4 to S1 dermatomes and dysthaesia to the surrounding dermatomes. He was on anti-hypertensive therapy in addition to warfarin for AF. A week previously the patient had been on holiday in Spain and had fallen. He complained of pain and swelling around the right iliac crest and was able to weight-bear almost immediately. Over the next 2 days the pain worsened and he noticed a weakness in dorsi-flexion of the foot and some numbness. A pelvic radiograph at the Emergency Dept. was taken which demonstrated a longitudinal fracture of the right iliac blade (Fig. 1). On arrival in orthopaedic clinic he mobilised with a frame and had an obvious foot drop. Examination revealed plantar flexion, dorsi-flexion and EHL function of just 1/5 (MMC scale). In addition the patient also had anaesthesia and pain in an L4 to S2 dermatomal distribution with brisk reflexes. After discussion with our radiology colleagues, an MRI of the hip, pelvis and lumbar spine was performed specifically to exclude nerve root avulsion injuries. The spine images were unremarkable, but the pelvic films showed amass suggestive of a haematoma (see Figs. 2 and 3). The imageswere sent to a specialist regional orthopaedic centre to rule out a sarcoma. Over the next 8 months, the patient’s neurological symptoms slowly improved, but there was some residual neurological deficit.